Layne GeoConstruction is a market leader in vibro compaction and densification performance utilizing a wide range of electrical vibrators, such as the Model V220, V23 and V330 vibroprobes. These electrical vibrators are the most versatile machines for densification and installing both wet top feed and dry bottom stone columns as well as for vibro concrete columns.

						Stone columns have been used to improve a wide range of soil types ranging from very soft silty clayey soils and peat to subsoils less suitable for vibro compaction. In areas with frequent seismic activities, vibratory ground improvement can reduce the potential for liquefaction and ground deformation due to lateral spreading.
Penetration The Vibroprobe penetrates by vibration and aid of compressed air or water to the required depth.		Installation The stone column is installed by adding gravel through the separate gravel duct alongside the Vibroprobe.		Completion The surface is levelled and rolled compacted.

Vibro stone columns are created by adding crushed stone through a separate duct along side of the vibroprobe. The stone column serves as a vertical drain, thus assisting the dissipation of excess pore water pressure caused by unexpected rapid loadings or earthquakes, making soil liquefaction less likely to occur.

Dry bottom feed stone columns are employed to densify sandy soils in place by means of an electric vibrating unit, and installing granular columns of crushed gravel during the process.

Dry bottom feed stone columns are most suitable for application in reduction of differential settlements, as the stone 

column installation adapts itself to changing soil conditions from soft to dense conditions and thus reduces potential differential ground settlement behavior.

Stone Columns act as vertical drains, thus reducing the excess pore pressures that lead to liquefaction.

The earthquake induced shear stress is distributed onto soil and columns in a ratio proportional to the stiffness ration between materials.